A high-lift system of an aircraft is used for purposefully increasing the lift of the aircraft, particularly during take-off and landing, and to thereby reduce the inflow velocity against the lifting surfaces required for the take-off and for the flight. Many different types of high-lift systems, which comprise extendable high-lift surfaces on leading and/or trailing wing edges, are known from practical applications. In addition, different techniques are used for moving high-lift surfaces, wherein the concept of a central drive unit and rotating driveshafts, which are driven by said drive unit and extend into the wing halves, is widely used. Driving stations are mechanically connected to the driveshaft and convert a rotation into a motion of the associated flap. In addition to linear spindle-based devices, devices with multi-link chains moved by a rotating drive lever are also used for this purpose.
In the manufacture of an aircraft, subassemblies responsible for a motion of components are always adjusted individually such that predefined functions and motion paths may be exactly realized. In high-lift systems that are based on a central drive unit, in particular, it may be expected that certain play may occur along the kinematic chain between the drive unit and the driven point of a flap. Mechanical play may be expected, in particular, in a “dropped-hinge” design, in which a rotary actuator driven by the driveshaft moves a drive lever that is pivotably coupled to a flap, which is likewise mounted in a pivotable fashion. This may manifest itself in that the flap in question is constantly pressed in the direction of a retracted position while the aircraft is airborne due to the lifting forces occurring on the flap.